Injury Fact Sheet: Os Trigonum Impingement Syndrome

By on November 17, 2012

This 1906 drawing from The American Journal of Roentgenology, Radium Therapy and Nuclear Medicine shows the Os Trigonum as the first labeled item at the top of the page. The structure is a bony prominence rising from the posterior aspect of the talus.


The posterior aspect of the talus can sometimes have a long process extending from it.  This process is called Stieda’s Process.  In certain individuals, Stieda’s Process is not present and they develop a small ossicle of bone attached to the talus by fibrous tissue.  This ossicle is called the Os Trigonum.

Causes & Symptoms:

While these variations do not present any problems in non-dancers, continual pointing of the foot (plantarflexion) and standing en demi-pointe or pointe can lead to an impingement of the Os Trigonum.  This condition is characterized by pain in the posterolateral ankle, especially during plantarflexion.  Os Trigonum Impingement may also occur as a secondary condition to Talar Compression Syndrome.


Conservative treatments range from anti-inflammatory drugs and physical therapy, to coriticosteroid injections and/or a plaster cast for 3-4 weeks.  If ineffective, surgical removal of the Os Trigonum or Stieda’s process can provide relief of Talar Compression and Os Trigonum Impingement.  A study of 6 dancers who all received surgical intervention for Talar Compression participated in a follow-up study seven years after surgery.  All six dancers felt no relief from conservative treatments and opted for surgury.  In this case, all six dancers returned to dancing and were asymptomatic seven years later.

** Note: Fact sheets are compiled from peer-reviewed resources, and is intended for reference only.  For a complete list of references, click here.  In the event of an injury, seek advice from a licensed health professional.  The original content of this site is protected by copyright and may be shared, but not be republished without permission.  For full disclaimers and disclosures, visit our policies.

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